Systems and methods for detecting wear of brake pads

ABSTRACT

A system can be used to indicate wear of a brake pad. The system can include a brake housing, a brake pad mechanically coupled to the brake housing, and a sensor mechanically coupled to the brake pad. The sensor can determine when the brake pad has been worn to a predetermined location by a rotating portion of a wheel. The system can also include an electronic module electrically coupled to the sensor and mechanically coupled to the brake housing. The electronic module can include a radio frequency antenna configured to wirelessly receive radio frequency energy from an external radio frequency transmitter, and an energy converter electrically coupled to the radio frequency antenna. As well, the electronic module can include an internal transmitter electrically coupled to the energy converter and the radio frequency antenna.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 62/230,732; filed Jun. 15, 2015; and entitled BRAKE WEARINDICATOR DEVICE. The entire contents of U.S. Provisional PatentApplication No. 62/230,732 are incorporated herein by reference.

This application claims the benefit of U.S. Provisional PatentApplication No. 62/231,607; filed Jul. 11, 2015; and entitled SYSTEM ANDMETHOD TO DETECT THE WEARING STATUS OF A VEHICLE'S BRAKE PAD. The entirecontents of U.S. Provisional Patent Application No. 62/231,607 areincorporated herein by reference.

This application claims the benefit of and is a continuation of U.S.Nonprovisional patent application Ser. No. 14/829,283; filed Aug. 18,2015; and entitled SYSTEMS AND METHODS FOR DETECTING WEAR OF BRAKE PADS.Patent application Ser. No. 14/829,283 claims the benefit of U.S.Provisional Patent Application No. 62/178,660; filed Apr. 17, 2015; andentitled BRAKE WEAR INDICATOR SYSTEM. The entire contents of patentapplication Ser. No. 14/829,283 and Provisional Patent Application No.62/178,660 are incorporated herein by reference.

This application claims the benefit of PCT Patent Application No.PCT/US16/27998; filed Apr. 16, 2016; and entitled SYSTEMS AND METHODSFOR DETECTING WEAR OF BRAKE PADS. The entire contents of PatentApplication No. PCT/US16/27998 are incorporated by reference herein.

This application claims the benefit of and is a continuation-in-part ofU.S. Nonprovisional patent application Ser. No. 15/132,757; filed Apr.19, 2016; and entitled SYSTEMS AND METHODS FOR DETECTING WEAR OF BRAKEPADS. The entire contents of patent application Ser. No. 15/132,757 areincorporated by reference herein.

BACKGROUND

1. Field

The invention is directed in general to vehicle brake pads, and morespecifically, to brake pad wear sensors to measure the actual amount ofwear of a brake pad.

2. Description of Related Art

Vehicle maintenance requires periodic inspection of brake pads in orderto assess the deterioration of the brake pads and ultimately determinewhen the brake pads need to be replaced. Failure to periodically performthis inspection can result in accidents due to brake malfunctions, whichcan result in danger to vehicle occupants and costly repairs to thevehicle.

Accordingly, brake inspections are required for various types of brakingsystems, such as drum-based brakes, in which a padded “shoe” pressesagainst the wall of the wheel's drum, and disk brakes, in which two padspress against opposing sides of the rotating wheel disk (rotor). In thedisk brake system, the rotor is a hard metal rotating disk, which isattached to the rotating wheel. Two brake pads made of relatively softmaterial are located on both sides of the rotor at close proximity. Whenthe brake pedal is depressed, the two pads are forced towards the rotorto provide friction force that slows the wheel's rotation. As timeprogresses, the brake pads can become thinner and may need to bereplaced. In most vehicles, it is not obvious to the vehicle operator asto when the brake pads need to be replaced because each wheel often hasto be removed to inspect the brake pads. Consequently, the brake pad cantotally wear out and the hard metal pad carriers (also called padholders) can come in contact with the rotor causing substantial damageand creating dangerous and inefficient braking of the vehicle.

In order to improve the inspection process, some vehicles can includeembedded sensors to indicate excessive pad wear. As shown in FIG. 1,some systems can include a contact sensor attached in parallel to theinternal wall of the pad holder or embedded in the pad at a specificdistance from the pad holder. When the pad is worn to a point where itneeds to be replaced, the sensor can establish electrical contact withthe rotor. An electrical wire can convey the information to thevehicle's dashboard to generate a visual alarm indication for thevehicle operator. As further shown in FIG. 1, some vehicles may employ adistance sensor, which can continuously measure the distance between thetwo pad holders and thereby provide the information via electrical wiresto the vehicle's dashboard.

There are several disadvantages of these systems, namely, undue falsepositives indicating to the vehicle operator to replace the brake pads.Car manufacturers may incur substantial liability for any false negativeoccurrences. In other words, if the brake pad is in need of replacementand the system does not generate an alarm, and a consequent accidentoccurs, the manufacturer may be responsible due to the fact that noalarm was generated. Consequently, the sensors and associated alarmindications may be designed to be overly sensitive to avoid the falsenegative scenario. Even still, a rupture in the wires connecting thesensor to the dashboard can also produce an alarm not related to theactual condition of the brake pad. This false positive indication canbecome so frequent and so disturbing to vehicle operators, that manyoperators may neutralize or deactivate the system entirely, therebydefeating the whole purpose of the system.

Another disadvantage to the “dashboard approach” is that it does nottypically provide specific information about which brake pad needs to bereplaced. Because brake pads may wear at different rates, the operatorwill still have to remove all the wheels to determine which pad is inneed of maintenance. For vehicles, such as large trucks with manywheels, in which removal of wheels is costly and labor intensive, thedashboard approach can provide little value. Thus, there is a need fordevices and methods to allow reliable inspection of brake pads withoutremoving the wheels.

SUMMARY

The present disclosure includes systems for indicating wear of a brakepad. Systems can include a brake housing; a brake pad mechanicallycoupled to the brake housing; and a sensor mechanically coupled to thebrake pad. The sensor can determine when the brake pad has been worn toa predetermined location by a rotating portion of a wheel. The systemcan also include an electronic module electrically coupled to the sensorand mechanically coupled to the brake housing or located in closeproximity to the brake housing. The electronic module can include aradio frequency antenna configured to wirelessly receive radio frequencyenergy from an external radio frequency transmitter; and an energyconverter electrically coupled to the radio frequency antenna. Theenergy converter can be configured to transform radio frequency energyto supply energy. The electronic module can also include an internaltransmitter electrically coupled to the energy converter and the radiofrequency antenna. The internal transmitter can be powered by the supplyenergy and configured to wirelessly transmit electrical information tothe external radio frequency transmitter via the radio frequencyantenna.

Systems can also include the external radio frequency transmittercommunicatively coupled to the radio frequency antenna. The electronicmodule can be located within 12 inches of the brake pad.

The rotating portion can comprise one of a rotating disk and a drum. Aswell, the sensor can be at least partially embedded within the brakepad.

The sensor can include an electrically conductive filament embedded inthe brake pad at a predetermined distance with respect to a brake padsurface that contacts the rotating portion of the wheel. The electricalconductivity as measured by the conductive filament can decrease whenthe brake pad is worn to at least the predetermined location.

The electronic module can include memory mechanically coupled to thebrake housing and electrically coupled to the energy converter and theinternal transmitter. The memory can store at least one of initial brakepad thickness information, brake pad installation information, and wheelidentification information.

Systems can also include a pad holder mechanically coupled to the brakehousing. The sensor can be configured to determine distance between thepad holder and a brake pad surface that contacts the rotating portion ofthe wheel.

In embodiments, the sensor can be a first sensor embedded within thebrake pad at a first thickness of an internal portion of the brake pad.The system can also include a second sensor embedded within the brakepad at a second thickness of the internal portion of the brake pad. Thesecond sensor can determine when the brake pad has been worn to a secondpredetermined location. As well, the system can include a third sensorembedded within the brake pad at a third thickness of the internalportion of the brake pad. The third sensor can determine when the brakepad has been worn to a third predetermined location.

The disclosure can also include systems for indicating wear of a brakepad, which includes a brake pad having electrically conductive materiallocated within an internal portion of the brake pad. The internalportion can be at least partially conductive and can have apredetermined electrical resistivity. The system can also include atleast two electrodes embedded within the brake pad. The at least twoelectrodes can measure the electrical resistivity of the internalportion of the brake pad. The electrical resistivity can indicate athickness of the internal portion of the brake pad after the internalportion has been eroded by a rotating portion of a wheel. The electricalresistivity can be inversely proportional to a thickness of the internalportion.

Systems can also include a pad holder mechanically coupled to the brakepad; and a resistivity meter electrically coupled to the at least twoelectrodes and located between the brake pad and the pad holder. Theresistivity meter can determine the electrical resistivity.

Embodiments of the system can also include a resistivity meterelectrically coupled to the at least two electrodes and located along adashboard of a vehicle. Systems can also include a status indicationdisplayed on the dashboard. The status indication can be indicative ofthe thickness of the internal portion of the brake pad. The statusindication can comprise an alarm that alerts a user that the thicknessof the internal portion meets a predetermined thickness indicating thatthe brake pad needs to be replaced. The conductive material can compriseat least one of metallic particulate matter, conductive carbonparticulate matter, and a combination of metallic particulate matter andconductive carbon particulate matter.

Systems can include a radio frequency antenna configured to wirelesslyreceive radio frequency energy from an external radio frequencytransmitter. The radio frequency energy can generate electrical currentvia the electrically conductive material located within the internalportion of the brake pad. The electrical current can indicate theelectrical resistivity of the internal portion.

The disclosure also includes methods of determining thickness of a brakepad that impedes rotation of a wheel mechanically coupled to a vehicle.The thickness can be determined without removing the wheel from thevehicle. Methods can include wirelessly providing radio frequency energyfrom an external radio frequency transmitter to a radio frequencyantenna mechanically coupled to a brake housing that holds the brakepad; converting, by an energy converter electrically coupled to theradio frequency antenna, the radio frequency energy into supply energy;activating, by the supply energy, a sensor mechanically coupled to thebrake pad and electrically coupled to the energy converter and the radiofrequency antenna; wirelessly receiving, by the external radio frequencytransmitter, information regarding the thickness of an internal portionof the brake pad, wherein the external radio frequency transmitter iscommunicatively coupled to an internal transmitter electrically coupledto both the sensor and the radio frequency antenna; and displaying, bythe external radio frequency transmitter, an indication of the thicknessof the internal portion of the brake pad. The external radio frequencytransmitter may not be mechanically coupled to the vehicle.

The sensor can include an electrically conductive filament embeddedwithin the brake pad at a predetermined distance with respect to a brakepad surface that contacts the rotating portion of the wheel. Methods caninclude determining, by the sensor, whether the brake pad has been wornto the predetermined distance; and displaying, by the external radiofrequency transmitter, an indication of whether the brake pad has beenworn to the predetermined distance thereby indicating whether the brakepad needs to be replaced.

The internal portion of the brake pad can include electricallyconductive material such that the internal portion is at least partiallyconductive and has a predetermined electrical resistivity. The sensorcan be embedded within the internal portion and the sensor can detect anelectrical resistivity of the internal portion. The electricalresistivity can be inversely proportional to a thickness of the internalportion. Methods can further include determining the electricalresistivity of the internal portion of the brake pad; and displaying, bythe external radio frequency transmitter, the thickness of the internalportion to thereby indicate whether the brake pad needs to be replaced.

In embodiments, memory can be mechanically coupled to the brake housingand electrically coupled to the internal transmitter and the radiofrequency antenna. The memory can store brake pad thickness information,brake pad wear profile information, brake pad installation information,and wheel identification information. Methods can include displaying, bythe external radio frequency transmitter, an indication of brake padthickness information, brake pad wear profile information, brake padinstallation information, and wheel identification information.

Some embodiments can include a resistivity meter electrically coupled tothe radio frequency antenna and the energy converter. Methods caninclude displaying, by a dashboard of the vehicle, an indication ofreal-time thickness of an internal portion of a first brake pad.

Methods can also include displaying, by the dashboard of the vehicle, anindication of real-time thickness of an internal portion of a secondbrake pad; and displaying, by the dashboard of the vehicle, anindication of real-time thickness of an internal portion of a thirdbrake pad. Methods can also include displaying, by the dashboard of thevehicle, an indication of real-time thickness of an internal portion ofa fourth brake pad; displaying, by the dashboard of the vehicle, anindication of real-time thickness of an internal portion of a fifthbrake pad; and even displaying, by the dashboard of the vehicle, anindication of real-time thickness of an internal portion of a sixthbrake pad.

Methods can also include storing, by the memory, an initial electricalresistivity of the internal portion of the brake pad, and determining apresent electrical resistivity of the internal portion of the brake pad.In some embodiments, the indication of the thickness of the internalportion can be based upon a ratio of the initial electrical resistivityto the present electrical resistivity.

The embodiments described above include many optional features andaspects. Features and aspects of the embodiments can be combined.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages are described belowwith reference to the drawings, which are intended to illustrate, butnot to limit, the invention. In the drawings, like reference charactersdenote corresponding features consistently throughout similarembodiments. The above and other features of the present invention willbecome more apparent by describing in detail exemplary embodimentsthereof with reference to the accompanying drawings, in which:

FIG. 1 illustrates a brake system, according to a prior art embodiment;

FIG. 2 illustrates a brake system, according to embodiments of thepresent disclosure;

FIG. 3a illustrates a portion of a brake pad, according to embodimentsof the present disclosure;

FIG. 3b illustrates a portion of a brake pad, according to embodimentsof the present disclosure;

FIG. 4 illustrates a brake system, according to embodiments of thepresent disclosure;

FIG. 5 illustrates an electronic module, according to embodiments of thepresent disclosure;

FIG. 6 illustrates a vehicle dashboard, according to embodiments of thepresent disclosure; and

FIGS. 7, 8, and 9 depict flow diagrams showing methods of operatingbrake systems, according to some embodiments.

DETAILED DESCRIPTION

Although certain embodiments and examples are disclosed below, inventivesubject matter extends beyond the specifically disclosed embodiments toother alternative embodiments and/or uses, and to modifications andequivalents thereof. Thus, the scope of the claims appended hereto isnot limited by any of the particular embodiments described below. Forexample, in any method or process disclosed herein, the acts oroperations of the method or process may be performed in any suitablesequence and are not necessarily limited to any particular disclosedsequence. Various operations may be described as multiple discreteoperations in turn, in a manner that may be helpful in understandingcertain embodiments; however, the order of description should not beconstrued to imply that these operations are order dependent.Additionally, the structures, systems, and/or devices described hereinmay be embodied as integrated components or as separate components.

For purposes of comparing various embodiments, certain aspects andadvantages of these embodiments are described. Not necessarily all suchaspects or advantages are achieved by any particular embodiment. Thus,for example, various embodiments may be carried out in a manner thatachieves or optimizes one advantage or group of advantages as taughtherein without necessarily achieving other aspects or advantages as mayalso be taught or suggested herein.

LIST OF REFERENCE NUMERALS

-   10—Brake system-   12—Brake pad-   13—Internal portion-   14—Rotor-   16—Pad holder-   17—Brake housing-   18—Sensor-   19—Brake pad surface-   20—Electronic module-   21—Vehicle dashboard-   22—Antenna (e.g. a dashboard antenna and/or a radio frequency    antenna)-   24—Converter-   26—Transmitter-   28—Meter-   30—Memory-   32—Insulation-   34—Inner housing-   36—Predetermined location-   38—Predetermined distance-   40—External transmitter-   41—Wireless communication-   42—Status indication-   44—Alarm

INTRODUCTION

The brake system 10, as disclosed, can address the disadvantages aspreviously described. For example, embodiments of the brake system 10can wirelessly provide information regarding wear of a brake pad 12 of avehicle. In this regard, a technician performing an inspection of thebrake pad 12 may interrogate the brake system 10, via an externalwireless transmitter, and thereby determine the wear of the brake pad12. The technician may thereby perform the inspection without having toremove the individual wheel from the vehicle. In this regard, once thetechnician determines which brake pads 12 are in need of being replaced,only the wheels of worn or defective brake pads 12 may be removed tothereby replace the respective brake pads 12. These are just a fewbenefits and the person of ordinary skill in the art may appreciateadditional benefits.

Conductive Filament Embodiments

In regards to specific embodiments, FIG. 2 illustrates a brake system 10for indicating wear of a brake pad 12, such as a brake pad used in avehicle disk brake system (as shown) or a vehicle drum brake system (notshown). In some embodiments, the brake system 10 can include a brakehousing 17 and a brake pad 12 mechanically coupled to the brake housing17. As shown in FIGS. 2, 3 a, and 3 b, the brake system 10 can include asensor 18 to determine when the brake pad 12 has been worn to apredetermined location 36, or thickness, by a rotating portion of awheel, such as a rotor 14 (i.e. rotating disk) or a drum (not shown). Inother words, the sensor 18 can determine when an internal portion 13 ofthe brake pad 12 has worn by a predetermined distance 38, which canindicate a remaining thickness of the internal portion 13 to therebysignal when the brake pad 12 needs to be replaced.

In some embodiments, the brake system 10 further includes a pad holder16 mechanically coupled to the brake housing 17. In such embodiments,the sensor 18 can be configured to determine a distance between the padholder 16 and a brake pad surface 19 that contacts the rotor 14 or drum,which can be indicative of a remaining thickness of the internal portion13 of the brake pad 12.

The brake system can also include an electronic module 20 electricallyand/or communicatively coupled to the sensor 18. The electronic module20 can be coupled to the sensor 18 via a wireless or wired connection.As such, the electronic module 20 can be configured to receiveinformation from the sensor 18 and thereby transmit the information todevices communicatively coupled to the electronic module 20 for ultimateretrieval by a technician or vehicle operator. The electronic module 20can be mechanically coupled to the brake housing 17 and/or pad holder16. For example, the electronic module 20 can be located within 36inches, 24 inches, 12 inches, 6 inches, 3 inches of the brake pad 12, orcloser.

As shown in FIG. 3a , the sensor 18 can comprise an electricallyconductive filament disposed at a predetermined location 36 within aninternal portion 13 of the brake pad 12. Accordingly, the sensor 18 canmeasure electrical conductivity within the internal portion 13 of thebrake pad 12. In this regard, when the internal portion 13 is eroded (orworn) down to the predetermined location 36 of the sensor 18, theelectrical conductivity, as measured by the sensor 18, can decrease—andin some embodiments, the sensor 18 can measure the conductivity as zero.

Accordingly, the electronic module 20 can also include a meter 28, suchas a conductivity meter, that can be electrically and/or communicativelycoupled to the sensor 18. In this regard, when the internal portion 13of the brake pad 12 is worn down to the sensor 18 and the conductivefilament is thereby torn from the sensor 18, the electrical conductivityof the filament measured by the meter 30 can drop to zero. The drop inconductivity can thereby indicate that the internal portion 13 has beenworn down to the predetermined location 36, which can mean that thebrake pad 12 needs to be replaced.

In some embodiments, the sensor 18 can be mechanically coupled to thebrake pad 12. The sensor 18 can be fully embedded within the brake pad12, at least partially embedded within the brake pad 12, or even locatedadjacent to the brake pad 12. Even still, the sensor 18 can be remotelylocated with respect to the brake pad 12. In such embodiments, thesensor 18 can detect various indications of wear of the internal portion13 of the brake pad 12 via a wireless and/or wired connection.

As illustrated in FIG. 3b , the brake system 10 can include more thanone sensor 18. For example, the brake system 10 can include two or moresensors 18 disposed at different predetermined locations 36, orthicknesses, within an internal portion 13 of the brake pad 12. In thisregard, multiple sensors 18 can indicate different levels of wear of thebrake pad 12. For example, a first sensor 18 a can be disposed at afirst predetermined location 36 a, such as to indicate when 25% of theoriginal thickness of the internal portion 13 has been worn away. Insome embodiments, a second sensor 18 b can be disposed at a secondpredetermined location 36 b, such as to indicate when 50% of theoriginal thickness of the internal portion 13 has been worn away. Evenstill, in some embodiments, a third sensor 18 c can be disposed at athird predetermined location 36 c, such as to indicate when 75% of theoriginal thickness of the internal portion 13 has been worn away.Generally, it should be appreciated that the brake system 10 can includeany number of sensors 18 disposed at various predetermined locations(i.e. heights or thicknesses) of the internal portion 13 to indicatevarious levels of wear.

In some embodiments, the electronic module 20 includes an antenna 22,such as a radio frequency antenna, configured to wirelessly receiveradio frequency energy from an external radio frequency transmitter 40.The electronic module 20 can also include an energy converter 24electrically coupled to the radio frequency antenna 22. The energyconverter 24 can receive radio frequency energy from the antenna 22whereby the converter 24 transforms the radio frequency energy intosupply energy, usually in the form of direct current (DC). The supplyenergy can thereby power other components of the electronic module 20,such as the meter 28, and other components discussed throughout thisdisclosure.

Furthermore, in some embodiments, the electronic module 20 includesmemory 30 electrically coupled to the antenna 22, energy converter 24,and/or meter 28. The memory 30 can also be powered by the supply energy.As well, the memory can be mechanically coupled to the brake housing 17via the electronic module 20. The memory 30 can store various data, suchas but not limited to, at least one of initial brake pad thicknessinformation (i.e. the thickness of the internal portion 13 when thebrake pad 12 was first installed), current brake pad thicknessinformation (i.e. the current thickness of the internal portion 13),brake pad wear profile information (i.e. any data related to wearprofiles of the internal portion 13), brake pad installation information(e.g. date, location, and the like), and wheel identificationinformation (i.e. the location of the wheel with respect to thevehicle—e.g. front driver-side wheel). This information can be valuableto assess the longevity of each of the brake pads 12. As well, theinformation can be useful when the brake pads 12 are installed ondifferent dates.

As well, the electronic module 20 can include an internal transmitter 26electrically coupled to the antenna 22, energy converter 24, meter 28,and/or memory 30. Like the other components of the electrical module 20,the internal transmitter 26 can be powered by the supply energy. Theinternal transmitter 26 can also be configured to wirelessly transmitelectrical information from the meter 28 and/or memory 30 to theexternal radio frequency transmitter 40. In some embodiments, theinternal transmitter 26 transmits the information to the external radiofrequency transmitter 40 via the radio frequency antenna 22.

Accordingly, the brake system 10 can also include the externaltransmitter 40 that can be electrically and/or communicatively coupledto the electronic module 20 via wireless connection 41. The externaltransmitter 40 can transmit the radio frequency energy to the antenna22. As well, the external transmitter 40 can simultaneously receiveinformation from the electronic module 20 in regards to the brake pad12. Accordingly, the external transmitter 40 can thereby display anindication of the information so that the technician and/or vehicleoperator can determine the status of the brake pad 12.

The external transmitter 40 can be operated in one or at least twomodes. For example, in a first mode, the external transmitter 40 can belocated within close proximity to each one of the brake pads 12, andthereby interrogate each brake pad 12 individually. The externaltransmitter 40 can also operate a second mode in which the externaltransmitter 40 interrogates more than one brake pad 12 or all of thebrake pads coupled to a vehicle at the same time. In this manner, theelectronic modules 20 and corresponding circuitry of each brake pad 12are energized at the same time. As well, information from each of thebrake pads 12 can be transmitted to the external transmitter 40 at thesame time. The external transmitter 40 can thereby process theinformation and display indications of the information (from all brakepads 12) so that the technician and/or vehicle operator can determinethe status of all the brake pads 12 at relatively the same time. In suchembodiments, because the external transmitter 40 is interrogating morethan one brake pad 12 and doing so at a greater distance than in thefirst mode, the external transmitter 40 may have to generate moreenergy, with respect to the first mode, to energize all of theelectronic modules 20 of all the brake pads 12.

Resistivity Brake Pad Embodiments

With reference to FIG. 4, a brake system 10 can include brake pads 12that are configured to detect electrical properties of the brake pad 12,which can indicate the thickness of an internal portion 13 of the brakepad 12. Accordingly, a traditional brake pad can be replaced by a brakepad 12 that is at least partially conductive to electrical current. Inthis manner, the inner portion 13 of the brake pad 12 can be doped withelectrically conductive material. Therefore, the inner portion 13 mayhave a combination of ceramic (non-conductive material) and conductivematerial (as doped throughout). The combination of materials can therebyconvert the inner portion 13 of the brake pad 12 into an electricalresistor with a resistivity (inversely) related to the thickness of theinner portion 13.

Accordingly, the electrical resistivity of the brake pad 12 can beperiodically or continuously measured by embedded electronic circuitry,such as a meter 28 coupled to sensors 18, such as electrodes, located atvarious points along the inner portion 13 of the brake pad 12. It shouldbe appreciated that the meter 28 can be configured to measureconductivity, resistivity, and/or the like.

The brake system 10 can include at least two electrodes, or sensors 18,embedded within the brake pad 12. The at least two electrodes 18 canmeasure the electrical resistivity of the internal portion 13 of thebrake pad 12 between the electrodes 18. As such, the electricalresistivity can indicate a thickness of the internal portion 13 of thebrake pad 12 after a rotating portion of a wheel, such as a rotor 14 ordrum, has eroded the brake pad surface 19 of the internal portion 13. Insome embodiments, the electrical resistivity can be inverselyproportional to a thickness of the internal portion 13. For example, asthe thickness of the internal portion 13 decreases, the electricalresistivity of the internal portion 13 can increase. Accordingly, as thethickness of the internal portion 13 decreases, the conductance of theinternal portion 13 can decrease.

As well, because the thickness, size, and electrical resistivity of theinternal portion 13 of brake pads 12 can vary from pad to pad, as longas the brake system 10 can determine the initial electrical resistivityof the initial thickness of the internal portion 13, then the brakesystem 10 can determine any thickness of the internal portion 13thereafter. For example, if the brake system 10 determines that theinitial electrical resistivity is X, then when X increases to 2X, thethickness of the internal portion 13 of the brake pad is 50% of theinitial thickness. Moreover, if the initial electrical resistivity is X,then when X increases to 3X, the thickness of the internal portion 13 ofthe brake pad is 33.33% of the initial thickness. Generally, as long asthe brake system 10 is able to determine an electrical resistivity of athickness of the internal portion 13 of the brake pad 12, then the brakesystem 10 can determine any other thickness thereafter.

In some embodiments, the conductive material can comprise conductivecarbon material, such as graphite, and/or metallic particulate compoundthat reduces the resistivity of the inner portion 13 of the brake pad 12in addition to hardening the material of the inner portion 13. Evenstill, in some embodiments, the conductive material can include acombination of metallic particulate matter and conductive carbonparticulate matter.

With reference to FIGS. 5 and 6, the brake system 10 can also includevarious electrical components, housed within an electronic module and/ora vehicle dashboard 21, such as, an antenna 22, meter 28, and memory 30.As previously described, the radio frequency antenna 22 can beconfigured to wirelessly receive radio frequency energy from an externalradio frequency transmitter 40. The radio frequency energy can therebygenerate electrical current via the electrically conductive materiallocated within the internal portion 13 of the brake pad 12. As such, theelectrical current can indicate the electrical resistivity of theinternal portion 13.

The electronic module 20 can be disposed within various locations of thevehicle. In some embodiments, the electronic module 20 is disposedwithin an inner housing of the brake pad 12, which is electricallyisolated from the conductive portion of the internal portion 13 of thebrake pad 12 by insulation 32. In some embodiments, the electronicmodule 20 is located in close proximity to the brake housing 17, and canbe coupled with the sensors 18 via a wireless or wired connection. Evenstill, in some embodiments, the electronic module 20 is located withinthe dashboard 21 of the vehicle and can thereby be coupled with thesensors 18 via a wireless or wired connection.

In some embodiments, whereby at least part of the electronic module 20is located on or near the dashboard 21 of the vehicle, the system canfurther include a status indication 42 displayed on the dashboard 21.The status indication 42 can thereby indicate the thickness of theinternal portion 13 of the brake pad 12. In some embodiments, the statusindication 42 can include an alarm 44 that alerts a vehicle operator(i.e. user) that the thickness of the internal portion 13 meets apredetermined thickness. The predetermined thickness can indicatevarious wear levels of the internal portion 13 of the brake pad 12, suchas a level when the brake pad needs to be replaced.

The external transmitter 40 can be physically detached from the vehicleor physically integrated into the vehicle. Regardless of the location ofthe external transmitter 40, the external transmitter 40 can still becommunicatively and/or electrically coupled to the electronic module 20.For example, the external transmitter 40 can be located along thedashboard 21 of the vehicle, whereby the external transmitter 40continuously and/or periodically communicates with the electronic module20. It should be appreciated that any portion of the electronic module20 and/or external transmitter 40 can be located on the vehicle, such asalong the dashboard 21, and/or within close proximity of the brake pad12.

As well, any of the systems and methods described throughout thisdisclosure can be adapted and configured to fit into any type and/ormodel of motor vehicle or non-motor vehicle. For example, the brakesystem 10 can be used in cars, trucks, buses, recreation vehicles,military vehicles, armored vehicles, unmanned vehicles, experimentalvehicles, motorcycles, scooters, and the like. Even still, the brakesystem 10 can be attached to vehicles at various stages ofmanufacturing. For example, the brake system 10 can be built into thevehicle on the production line at the time the vehicle is manufactured.Even still, the brake system 10 can be sold as an after-market systemthat can be attached to any existing vehicle.

Methods of Detecting Thickness of a Brake Pad

As illustrated in FIGS. 7, 8, and 9, the disclosure also includes amethod of determining thickness of a brake pad 12 that impedes rotationof a wheel mechanically coupled to a vehicle. The thickness can bedetermined without removing the wheel from the vehicle.

As shown in FIG. 7, methods can include wirelessly providing radiofrequency energy from an external radio frequency transmitter 40 to aradio frequency antenna 22 mechanically coupled to a brake housing 17that holds the brake pad 12 (at step 700). As well, methods can includeconverting, by an energy converter 24 electrically coupled to the radiofrequency antenna 22, the radio frequency energy into supply energy (atstep 702). Even still, methods can include activating, by the supplyenergy, a sensor 18 mechanically coupled to the brake pad 12 andelectrically coupled to the energy converter 24 and the radio frequencyantenna 22 (at step 704).

Methods can also include wirelessly receiving, by the external radiofrequency transmitter 40, information regarding the thickness of aninternal portion 13 of the brake pad 12 (at step 706). In someembodiments, the external radio frequency transmitter 40 iscommunicatively coupled to an internal transmitter 26 electricallycoupled to both the sensor 18 and the radio frequency antenna 22. Aswell, methods can include displaying, by the external radio frequencytransmitter 40, an indication of the thickness of the internal portion13 of the brake pad 12 (at step 708). In some embodiments, the externalradio frequency transmitter 40 is not mechanically coupled to thevehicle.

As previously described, the sensor 18 can include an electricallyconductive filament embedded within the brake pad 12 at a predetermineddistance with respect to a brake pad surface 19 that contacts therotating portion of the wheel, such as a rotor 14. With reference toFIG. 8, methods can also include determining, by the sensor 18, whetherthe brake pad 12 has been worn to the predetermined distance (at step800). Methods can also include displaying, by the external radiofrequency transmitter 40, an indication of whether the brake pad 12 hasbeen worn to the predetermined distance (at step 802). The indicationcan thereby indicate whether the brake pad 12 needs to be replaced.

In some embodiments, the internal portion 13 of the brake pad 12 cancomprise electrically conductive material such that the internal portion13 is at least partially conductive and has a predetermined electricalresistivity. The sensor 18 can thereby be embedded within the internalportion 13 so that the sensor 18 can detect an electrical resistivity ofthe internal portion 13. In some embodiments, the electrical resistivitycan be inversely proportional to a thickness of the internal portion 13.Accordingly, methods can include determining the electrical resistivityof the internal portion 13 of the brake pad 12 (at step 804). As well,methods can include displaying, by the external radio frequencytransmitter 40, the thickness of the internal portion 13 to therebyindicate whether the brake pad 12 needs to be replaced.

Embodiments can also include memory 30 that can be mechanically coupledto the brake housing 17 and electrically coupled to the internaltransmitter 26 and the radio frequency antenna 22. The memory 30 canstore brake pad thickness information, brake pad wear profileinformation, brake pad installation information, and wheelidentification information. Methods can further comprise displaying, bythe external radio frequency transmitter 40, an indication of brake padthickness information, brake pad wear profile information, brake padinstallation information, and wheel identification information (at step806).

Embodiments of the brake system 10 can also include a resistivity meter28 that is electrically coupled to the radio frequency antenna 22 andthe energy converter 24. As illustrated in FIG. 9, methods can furtherinclude displaying, by a dashboard of the vehicle, an indication ofreal-time thickness of an internal portion 13 of a first brake pad 12(at step 900). Accordingly, methods can also include displaying, by thedashboard of the vehicle, an indication of real-time thickness of aninternal portion 13 of a second brake pad 12 (at step 902). Methods caninclude displaying, by the dashboard of the vehicle, an indication ofreal-time thickness of an internal portion 13 of a third brake pad 12(at step 904). Even still, methods can include displaying, by thedashboard of the vehicle, an indication of real-time thickness of aninternal portion 13 of a fourth brake pad 12 (at step 906). Methods canalso include displaying, by the dashboard of the vehicle, an indicationof real-time thickness of an internal portion 13 of a fifth brake pad 12(at step 908). Methods can even include displaying, by the dashboard ofthe vehicle, an indication of real-time thickness of an internal portion13 of a sixth brake pad 12 (at step 910).

Interpretation

The phrase “data associated with the brake pad”, as used in thedisclosure, can be interpreted to mean any type of data that is relatedto the vehicle, including digital computerized instructions to processbrake pad information and/or data.

None of the steps described herein is essential or indispensable. Any ofthe steps can be adjusted or modified. Other or additional steps can beused. Any portion of any of the steps, processes, structures, and/ordevices disclosed or illustrated in one embodiment, flowchart, orexample in this specification can be combined or used with or instead ofany other portion of any of the steps, processes, structures, and/ordevices disclosed or illustrated in a different embodiment, flowchart,or example. The embodiments and examples provided herein are notintended to be discrete and separate from each other.

The section headings and subheadings provided herein are nonlimiting.The section headings and subheadings do not represent or limit the fullscope of the embodiments described in the sections to which the headingsand subheadings pertain. For example, a section titled “Topic 1” mayinclude embodiments that do not pertain to Topic 1 and embodimentsdescribed in other sections may apply to and be combined withembodiments described within the “Topic 1” section.

Some of the devices, systems, embodiments, and processes use computers.Each of the routines, processes, methods, and algorithms described inthe preceding sections may be embodied in, and fully or partiallyautomated by, code modules executed by one or more computers, computerprocessors, or machines configured to execute computer instructions. Thecode modules may be stored on any type of non-transitorycomputer-readable storage medium or tangible computer storage device,such as hard drives, solid state memory, flash memory, optical disc,and/or the like. The processes and algorithms may be implementedpartially or wholly in application-specific circuitry. The results ofthe disclosed processes and process steps may be stored, persistently orotherwise, in any type of non-transitory computer storage such as, e.g.,volatile or non-volatile storage.

The various features and processes described above may be usedindependently of one another, or may be combined in various ways. Allpossible combinations and subcombinations are intended to fall withinthe scope of this disclosure. In addition, certain method, event, state,or process blocks may be omitted in some implementations. The methods,steps, and processes described herein are also not limited to anyparticular sequence, and the blocks, steps, or states relating theretocan be performed in other sequences that are appropriate. For example,described tasks or events may be performed in an order other than theorder specifically disclosed. Multiple steps may be combined in a singleblock or state. The example tasks or events may be performed in serial,in parallel, or in some other manner. Tasks or events may be added to orremoved from the disclosed example embodiments. The example systems andcomponents described herein may be configured differently thandescribed. For example, elements may be added to, removed from, orrearranged compared to the disclosed example embodiments.

Conditional language used herein, such as, among others, “can,” “could,”“might,” “may,” “e.g.,” and the like, unless specifically statedotherwise, or otherwise understood within the context as used, isgenerally intended to convey that certain embodiments include, whileother embodiments do not include, certain features, elements and/orsteps. Thus, such conditional language is not generally intended toimply that features, elements and/or steps are in any way required forone or more embodiments or that one or more embodiments necessarilyinclude logic for deciding, with or without author input or prompting,whether these features, elements and/or steps are included or are to beperformed in any particular embodiment. The terms “comprising,”“including,” “having,” and the like are synonymous and are usedinclusively, in an open-ended fashion, and do not exclude additionalelements, features, acts, operations and so forth. Also, the term “or”is used in its inclusive sense (and not in its exclusive sense) so thatwhen used, for example, to connect a list of elements, the term “or”means one, some, or all of the elements in the list. Conjunctivelanguage such as the phrase “at least one of X, Y, and Z,” unlessspecifically stated otherwise, is otherwise understood with the contextas used in general to convey that an item, term, etc. may be either X,Y, or Z. Thus, such conjunctive language is not generally intended toimply that certain embodiments require at least one of X, at least oneof Y, and at least one of Z to each be present.

The term “and/or” means that “and” applies to some embodiments and “or”applies to some embodiments. Thus, A, B, and/or C can be replaced withA, B, and C written in one sentence and A, B, or C written in anothersentence. A, B, and/or C means that some embodiments can include A andB, some embodiments can include A and C, some embodiments can include Band C, some embodiments can only include A, some embodiments can includeonly B, some embodiments can include only C, and some embodimentsinclude A, B, and C. The term “and/or” is used to avoid unnecessaryredundancy.

While certain example embodiments have been described, these embodimentshave been presented by way of example only, and are not intended tolimit the scope of the inventions disclosed herein. Thus, nothing in theforegoing description is intended to imply that any particular feature,characteristic, step, module, or block is necessary or indispensable.Indeed, the novel methods and systems described herein may be embodiedin a variety of other forms; furthermore, various omissions,substitutions, and changes in the form of the methods and systemsdescribed herein may be made without departing from the spirit of theinventions disclosed herein.

The following is claimed:
 1. A system for indicating wear of a brake padattached to a vehicle, comprising: a brake housing; a brake padmechanically coupled to the brake housing; a sensor mechanically coupledto the brake pad, wherein the sensor determines whether the brake padhas been worn to a predetermined location by a rotating portion of awheel; an on-board electronic module electrically coupled to the sensorand mechanically coupled to the vehicle, wherein the on-board electronicmodule comprises: a radio frequency antenna configured to wirelesslyreceive radio frequency energy from an external radio frequencytransmitter; an energy converter electrically coupled to the radiofrequency antenna, wherein the energy converter is configured totransform radio frequency energy to supply energy; an internaltransmitter coupled to the energy converter whereby the internaltransmitter is powered by at least a portion of the supply energy; andmemory coupled to the internal transmitter, wherein the memory storesdata associated with the brake pad, wherein the internal transmitter isconfigured to wirelessly transmit information from the sensor and thememory to the external radio frequency transmitter via the radiofrequency antenna.
 2. The system of claim 1, further comprising theexternal radio frequency transmitter communicatively coupled to theradio frequency antenna, and wherein the on-board electronic module islocated within 12 inches of the brake pad.
 3. The system of claim 2,wherein the rotating portion comprises one of a rotating disk and adrum, and wherein the sensor is at least partially embedded within thebrake pad.
 4. The system of claim 3, wherein the sensor comprises anelectrically conductive filament embedded in the brake pad at apredetermined distance with respect to a brake pad surface that contactsthe rotating portion of the wheel, and wherein electrical conductivitymeasured by the conductive filament decreases when the brake pad is wornto at least the predetermined location.
 5. The system of claim 1,further comprising a pad holder mechanically coupled to the brakehousing, wherein the sensor is configured to determine distance betweenthe pad holder and a brake pad surface that contacts the rotatingportion of the wheel.
 6. The system of claim 1, wherein the memorystores initial brake pad thickness information.
 7. The system of claim1, wherein the memory stores current brake pad thickness information. 8.The system of claim 1, wherein the memory stores brake pad installationinformation comprising at least one of a date and a location.
 9. Thesystem of claim 1, wherein the memory stores brake pad wear profileinformation.
 10. The system of claim 1, wherein the memory stores wheelidentification information comprising a location of the wheel withrespect to the vehicle.
 11. The system of claim 1, wherein the externalradio frequency transmitter is located adjacent to a dashboard of thevehicle.
 12. A method of determining thickness of a brake pad thatimpedes rotation of a wheel mechanically coupled to a vehicle, whereinthe thickness is determined without removing the wheel from the vehicle,the method comprising: determining, via a sensor mechanically coupled tothe brake pad, whether the brake pad has been worn to a predeterminedlocation by a rotating portion of the wheel; wirelessly receiving, viaan on-board electronic module electrically coupled to the sensor andmechanically coupled to the vehicle, radio frequency energy from anexternal radio frequency transmitter; transforming, via an energyconverter electrically coupled to a radio frequency antenna, radiofrequency energy to supply energy; powering an internal transmittercoupled to the energy converter by at least a portion of the supplyenergy; storing brake pad installation information and wheelidentification information via memory coupled to the internaltransmitter, wherein the memory is located on-board the vehicle; andwirelessly transmitting, via the internal transmitter, information fromthe sensor and the memory to the external radio frequency transmitterthrough the radio frequency antenna.
 13. The method of claim 12, furthercomprising communicatively coupling the external radio frequencytransmitter to the radio frequency antenna.
 14. The method of claim 12,further comprising determining distance between a pad holder and a brakepad surface that contacts the rotating portion of the wheel, wherein thepad holder is mechanically coupled to a brake housing.
 15. The method ofclaim 12, further comprising storing, via the memory, initial brake padthickness information.
 16. The method of claim 12, further comprisingstoring, via the memory, current brake pad thickness information. 17.The method of claim 12, further comprising storing, via the memory,brake pad wear profile information.
 18. The method of claim 12, furthercomprising displaying, by the external radio frequency transmitter, anindication of the thickness of the brake pad.
 19. The method of claim18, further comprising displaying, by the external radio frequencytransmitter, an indication of whether the brake pad has been worn to thepredetermined location thereby indicating whether the brake pad needs tobe replaced.
 20. The method of claim 18, further comprising displaying,by the external radio frequency transmitter, the thickness of the brakepad.